But a surprising number of people know the situation only too well. For them the film The War of the Roses, a black comedy in which Kathleen Turner and Michael Douglas loathe each but remain wedded to their house, has a horribly familiar ring. Whatever the reason, they found themselves trapped behind four walls with a partner they had grown to hate.
Rachel, in her 40s with two children, one from a previous relationship, had no idea that the end of her marriage would leave her a virtual prisoner in the family home for two years.
The house was in her husband's name, while she paid the housekeeping bills. Negotiations proved impossible while they were still living there together.
"My husband refused to move out but would not let me leave with our son, who was a few months old. I came back one weekend to find all my clothes moved to the small study, where there was only a camp bed. He also barred me from the sitting room. I was only allowed to use the children's rooms and the kitchen. When I heard his key in the lock it sent a shiver through me: the whole atmosphere changed at once."
By the second year, Rachel says, their home was a battleground in the fight for their son, and moving out would have seemed like deserting him. Her post was opened and she found her phone calls were recorded. She describes it as living in enemy territory: "Once a week we met in the sitting room to try to sort things out. I would go with my heart in my mouth like a schoolgirl. We had mediators, lawyers and social workers, but it was his word against mine. I felt as though I was being driven insane. I wanted to run out into the street and yell."
Rachel, now divorced and living on the outskirts of London with her son (he shares residency with the father) in a house bought by her husband, is one of thousands whose situation is lucrative for lawyers and estate agents: from one broken marriage could come three transactions.
The West Sussex estate agency, Henry Adams and Partners, says it is their biggest sector and growing. FPD Savills, property consultants, has a litigation support department almost entirely for sorting out the divorces of the wealthy.
Second homes come into their own during domestic strife. Indeed, a shortage of funds is the main reason a couple stays in the same house while going through their divorce. During the recession, negative equity forced many people reluctantly to co-habit.
Until property price rises released them, they kept out of each other's way, either by dividing the house into no-go areas or by leaving as the other returned. If one partner wants to stay put, the property and contents can become the last weapon in a bitter dispute.
Emma Stead, in the Fulham office of FPD Savills (Gemma Craven's patch of London), found a house recently for a woman whose husband refused to move out of their home even though he intended to live with his lover: "The wife was in a high-earning city job and had to find a new home. Until the divorce she was juggling her life and those of her nanny and children to avoid their paths crossing. Fortunately he travelled a fair bit."
But perhaps there are signs of a new maturity among parting couples. Gillian met her husband while he was still living with his wife. Their marriage was in its final death throes but neither could afford to move out.
"His wife would leave a message on the answer phone if she was going to be away," Gillian recalls. "After an evening out we would check to see whether we could go back to his flat. They were still sharing the same bed, so one night I might be sleeping in it, the next his wife. On one occasion when she found my underwear she washed it for me. I would always try to be out the next morning before she returned.
"In a way it was civilised. But years on, my husband is still bitter that she ended up with the flat."
! Changing the locks won't work. Matrimonial home rights include the right not to be evicted or excluded without a court order. Adultery is no basis for a court order. Unless violence is involved, in which case the courts would grant an injunction, sitting it out while the divorce goes through may be the only route.
! If a man is really bolshie, a court can make rulings about occupation and ownership on the grounds of unreasonable behaviour. He may be allowed to stay a month or plan a withdrawal financially. Stay for longer than six months after adultery is discovered and you cannot divorce for unreasonable behaviour.
! Courts balance the interests of both parties, particularly if there are children. Fear of losing that contact often stops men leaving. Courts will note if a woman has left her children: mothers beware. Unmarried couples should be co-owners. If not they should sign a declaration of trust.
Information supplied by Hazel Wright, a family lawyer at Cumberland Ellis and Peirs (0171 242 0422)